Preventing water supply disruptions and preserving trees in Shanghai

Nov 2007

China

The rapid development of cities put huge
pressures on the infrastructure which means
that traditional solutions fail in a relatively
short time. Such was the case in Shanghai
where, after only 20 years, an iron water
main in a congested inner suburb needed
urgent replacement.
The solution was PE relining. Requiring only
30 small pits and a mere three months
time, the Shanghai Pudong Water Company
replaced 2.6 km of water pipes with a
durable system, ensuring minimal disruption
for residents and preservation of the
surrounding greenery.

Improving efficiency of the water supply is a key
element to ensure sustainable management of
the resource – particularly in areas of high water
stress and rapid development.
Whether caused by decaying infrastructure or
poor pipe standards, water leaks and service disruption
are a plague affecting many networks and
cities around the world.
In mega-cities like Shanghai, the renovation of
water networks has to satisfy many sustainability
challenges.

With a population of 2.8 million people, Pudong
is one of the most vibrant areas of Shanghai in
China. After only 20 years of operation, a 2.6
km cast iron pipe network in the area has begun
showing signs of age. Leakage has occurred at
the joints and across parts of the pipe, resulting
in frequent repair and maintenance. The pipeline
had to be repaired 36 times in a period of
merely four years, causing disruptions to residents
in their daily lives. The city water authority,
the Shanghai Pudong Water Company, decided
to replace this section of the pipeline and started
evaluating alternative options.

Ensuring minimal disruptions

The Shanghai Pudong Water Company required
a durable, long lasting and cost-effective solution.
Other challenges included ensuring minimal disruption
to the residents living in the Pudong area
and preserving the surrounding greenery.
The area where the defective pipeline was buried
comprises two main roads lined with 400 trees.
The traditional technique of open trenching would
mean severe disruption to traffic and felling of all
400 trees.
Furthermore, water flow to residents had to be
restored quickly after the public works while the
hydraulic capacity of the existing network had to
be maintained.

Applying trenchless installation

The job was contracted to Shanghai Pudong
Water Supply & Drainage Construction Engineering
Co. Ltd, a subsidiary of Sade, which is part
of the Veolia Water Group. To minimise damage
to the environment and disruption to local residents,
and to cope with the hydraulic design,
the company decided to employ a trenchless
close-fit technique called “Swagelining” using
polyethylene PE100 pipes. The pipe chosen is
produced using the BorSafe™ PE100 compound
from Borouge and was recommended by Shanghai
Chinaust Plastics Corp. Ltd. – a market leader
in the pipe manufacturing industry.
The trenchless technique would ensure minimal
disruption to traffic, conserve the environment
and maintain distribution of a high water flow
to the local community after renovation work
is complete.

Durable, long lasting pipeline

A total of only 30 pits were dug to insert the PE
pipe sections and connect them to the other
sub-networks in the pipeline. Project work
began at the end of July 2006 with installation
of the bypass scheduled to be completed within
three months.
Besides its durability and ease of installation,
the new PE pipe section ensures drinking water
to the Pudong community throughout its long
service life-cycle and prevents leakage.
In addition, 400 trees were saved and will continue
to provide much needed greenery and
shade to the local residents.